Dependable infrastructure systems

1
Dependable infrastructure systems

• E.B. Fernandez

2
What is infrastructure

• One of the most important directions in homeland
  security is the protection of critical
  infrastructure.
• These are the systems that support our everyday
  life and environment
• The Dept. of Homeland Security has identified 14
  areas of concern including agriculture,
  information and telecommunications, food, energy,
  water, transportation, public health, and finance

3
Complex systems

• All these functions are controlled by systems
  which are complex and which are becoming
  increasingly interdependent
• Some are even mutually dependent, e.g. electric
  power generation may require oil and oil
  production may require electricity
• They are usually distributed, real-time systems,
  may use the Internet as communication medium, and
  may include wireless and embedded devices.
• They must be available always

4
Threats

• These systems are vulnerable to unintentional
  errors equipment failure, human errors, weather,
  and accidents
• They are also the object of intentional attacks
  external (hackers) and insiders (internal
  attacks).

5
Defenses

• We need to protect the information necessary to
  control and coordinate these systems against
  intentional attacks and accidental events.
• Also physical threats, access to buildings and
  installations
• It is necessary to extend the standard models of
  security and reliability to consider this
  combination

6
Process Control Systems
7
ICSs

• ICSs are implemented as supervisory control and
  data acquisition (SCADA) systems, distributed
  control systems (DCS), and Programmable Logic
  Controllers (PLCs)
• SCADA systems are highly distributed systems that
  control geographically scattered units (field
  devices) using centralized data acquisition and
  control (control center)
• Field devices control local operations such as
  opening and closing valves, collecting data from
  sensors, and monitoring for alarm conditions
• Typical uses include electric power systems,oil
  and gas pipelines, water utilities,
  transportation nets, intelligent buildings, and
  any application that requires remote monitoring
  and control.

8
SCADA

• SCADA architectures typically use layered
  architectures a hierarchy of architectural
  layers
• Typical requirements include 24x7 operation,
  real-time behavior, remote control, distribution
• To communicate between the Master control and its
  units the DNP3 (Distributed Network Protocol) is
  typically used
• From a security point of view, these systems are
  the most interesting because they are the most
  vulnerable the remote units are subject to
  physical attacks while the communication lines
  are subject to information attacks
• The main security objectives here include
  availability and integrity, confidentiality and
  non-repudiation are not very important..

9
Convergence of access control

• Homeland security has brought an interest in
  control of access to buildings and other physical
  structures.
• The need to protect assets in buildings and to
  control access to restricted areas such as
  airports, naval ports, government agencies, and
  nuclear plants, created a great business
  opportunity for the physical access control
  industry and a good amount of interest in the
  research community.
• Recognition that access control to information
  and access control to physical locations have
  many common aspects. The most basic model of
  access control uses a tuple (s,o,t), subject,
  object, access type. If we interpret s as a
  person (instead of an acting executing entity), o
  as a physical structure (instead of a
  computational resource), and t as a physical
  access type (instead of resource access), we can
  make an analogy where we can apply known results
  or approaches from information access control.

10
Access control unification

• One way to achieve this unification is using a
  conceptual abstraction for the definition of
  security requirements analysis and security
  patterns
• A pattern is an encapsulated solution to a
  recurrent problem in a given context. A security
  pattern defines a solution to a security problem.
  
• The use of patterns has been increasing in
  industry because of their potential to improve
  software quality. Security patterns have only
  recently become accepted by industry and
  Microsoft, IBM, and Sun have web pages on this
  topic. Also, two books have appeared recently. We
  have presented several security patterns for
  access control to information
• We examined existing systems, industry standards,
  and government regulations to find as patterns a
  core set of features that a physical access
  control system should have.
• From these patterns, it is possible to define
  more specific patterns that can be used to build
  systems for a given protocol or to define new
  protocols.

11
Pattern diagram
12
Access Control to Physical Structures

• Applies authentication and authorization to the
  control of access to physical units including
  alarm monitoring, relays, and time schedules that
  can control when things will happen.
• Example Building management wants to put in
  place an access control system to control access
  to certain zones and to control who can access
  the zones. They need to deny all access to
  certain zones after 5pm. They want to generate
  alarms when someone tries to access a zone for
  which they do not have permission and start
  monitoring alarms for all the exterior doors at
  8pm. Moreover, they want to turn on the main door
  light at 7pm.
• Context Physical environment with access control
  system where we need to control access and turn
  on/off devices based on time constrains.

13
Solution
Define the structure of an access control
system using an RBAC pattern. Integrate the
Alarms Monitoring and Relays patterns and
introduce the concept of a time schedule to
control when things can/must happen. Time
Schedules have two uses to control access times
and to configure automatic actions.
14
(No Transcript)
15
Ideas

• Describe through patterns the basic features and
  concepts for any Physical Access Control system,
  specialize models for specific environments
• Patterns can guide the design of physical access
  control systems or they can be used to evaluate
  current products or standards
• Extensions dynamic restriction of the locations
  where a suspicious user could go or
  reconfiguration of exits in case of emergencies
• Privacy-oriented restrictions
• Combination with context-based access control

16
More ideas

• Patterns for SCADA systems and for dependable
  SCADA systems
• Dependability patterns in general
• Models to combine information and physical access
  control
• Use of identity and context for authentication
  and access control